FISH analysis for apparently simple terminal deletions of the X chromosome: identification of hidden structural abnormalities

We report on fluorescence in situ hybridization (FISH) analysis in 30 mosaic or nonmosaic females diagnosed as having apparently simple terminal X deletions by standard G-banding analysis. FISH studies for DXZ1, the Xp and Xq telomere regions, and the whole X chromosome painting were carried out for the 30 females, indicating rearranged X chromosomes with signal patterns discordant with terminal deletions in 6 cases: one dic(X)(DXZ1++) chromosome, two der(X)(qtel++) chromosomes, one Xq- (qtel+) chromosome, and two der(X)(ptel++) chromosomes. Additional FISH studies were performed for the 6 cases using probes defining 12 loci on the X chromosome, showing large Xp deletion and small Xp duplication in the dic(X)(DXZ1++) chromosome, partial Xp deletions and partial Xq duplications in the two der(X)(qtel++) chromosomes, an interstitial Xq deletion in the Xq- (qtel+) chromosome, and partial Xq deletions and partial Xp duplications in the two der(X)(ptel++) chromosomes. Clinical assessment of the 6 cases revealed tall and normal stature in the two mosaic cases with the der(X)(ptel++) chromosomes that were shown to be associated with SHOX duplication. The results suggest that unusual X chromosome rearrangements are often misinterpreted as simple terminal X deletions, and that FISH analysis is useful for precise structural determination and better genotype-phenotype correlation of the X chromosome aberrations.

Glia-related pathomechanisms in Alzheimer's disease: a therapeutic target?

Reactive glial cell properties could contribute to pathomechanisms underlying Alzheimer's disease by favoring oxidative neuronal damage and beta-amyloid toxicity. A critical step is apparently reached when pathological glia activation is no longer restricted to microglia and includes astrocytes. By giving up their differentiated state, astrocytes may lose their physiological negative feed-back control on microglial NO production and even contribute to neurotoxic peroxynitrate formation. Another consequence is the impairment of the astrocyte-maintained extracellular ion homeostasis favoring excitotoxic damage. By the production of apolipoprotein-E, triggered by the microglial cytokine interleukine-1beta, reactive astrocytes could promote the transformation of beta-amyloid into the toxic form. A pharmacologically reinforced cAMP signaling in rat glial cell cultures depressed oxygen radical formation in microglia and their release of TNF-alpha and interleukine-1beta, feed-forward signals which mediate oxidative damage and secondary astrocyte activation. Cyclic AMP also favored differentiation and expression of a mature ion channel pattern in astrocytes improving their glutamate buffering. A deficient cholinergic signaling that increases the risk of pathological APP processing was compensated by an adenosine-mediated reinforcement of the second messenger calcium. A combination therapy with acetylcholine-esterase inhibitors together with adenosine raising pharmaca, therefore, may be used to treat cholinergic deficiency in Alzheimer's disease.

Smooth muscle cell proliferation at the vascular anastomotic stricture in rat aortotomy model

BACKGROUND

We recently suggested that a rat aortotomy model could be substituted for a vascular anastomotic stricture around a suture line. The aim of this study was to verify such a rat aortotomy model using proliferating cell nuclear antigen (PCNA) immunohistochemistry, which is a sensitive method for detection of proliferating cells in vascular tissue after injury.

METHODS

Longitudinal aortotomy was performed in the abdominal aorta of the rat subjects. The rats were sacrificed at 1, 2, 4 and 8 weeks following aortotomy (n=20 in each group). The control rats were sacrificed without aortotomy (n=20). The percentage of the lumen occluded by intimal thickening (I/M ratio) was calculated. All tissues were stained with antibodies against proliferating cell nuclear antigen (PCNA).

RESULTS

Values of I/M ratio were 8.5+/-4.4%, 15.6+/-9.5%, 11.8+/-5.5%, 9.6+/-6.2% at 1, 2, 4, 8 weeks following aortotomy in the injured groups and 0.4+/-0.1% in the controls, respectively. Those values in the injured group increased significantly as compared to the controls. There were also significant differences between one week and two weeks following aortotomy. The PCNA labeling index at one week following aortotomy (21.4+/-2.7%) was significantly higher than at two weeks following aortotomy (2.8+/-1.9%). SMCs in the intima at four and eight weeks following aortotomy were completely negative for PCNA.

CONCLUSIONS

The experimental rat aortotomy model was determined to be useful in the investigation of intimal thickening around the suture line.

Topographical analysis of p53 expression and DNA ploidy in early bronchial squamous cell carcinoma and preneoplastic lesions

The significance of p53 mutations and DNA aneuploidy in carcinoma cells has been investigated on the basis of a multi-step development theory of carcinogenesis. It has, however, not been determined whether these alterations can be used as diagnostic markers for the early detection of bronchial squamous cell carcinoma (BSqCC). To address this problem, we topographically investigated p53 alterations and DNA aneuploidy in 24 X-ray-negative, early BSqCC patients with various preneoplastic lesions and in 25 non-carcinoma patients with preneoplastic lesions. Bronchial lesions (n=88) were morphologically classified as hyperplasia (HP, n=5), squamous metaplasia (SM, n=23), low-grade dysplasia (LGD, n=14), high-grade dysplasia (HGD, n=11), intraepithelial carcinoma including 'carcinoma in situ' (CIS) (IEC, n=15), and microinvasive carcinoma (MIC, n=20). Immunohistochemistry for the p53 protein and image cytometry for DNA ploidy detection were performed in serial sections of each lesion. Overexpression of p53 protein was detected in 36, 73, and 65% of the HGD, IEC, and MIC lesions, respectively. Aneuploid DNA profiles were found only in carcinoma lesions, 33% in IEC and 85% in MIC. The topographical analysis revealed two types of early BSqCCs, one with adjacent preneoplastic lesions (sequential type, n=8) and another without such lesions (de novo type, n=16). The p53 protein was frequently overexpressed in both types (sequential type, 79%; de novo type, 62%). In the sequential type, however, the p53 protein was overexpressed in HGD lesions that were directly adjacent to p53-overexpressing carcinoma lesions without exception. The present topographical study suggests that p53 mutations play an important role in the carcinogenesis of BSqCC and that p53-overexpressing HGD lesions in sequential types should be regarded as 'truly' preneoplastic lesions that actually develop into carcinomas. In addition, our study demonstrated that DNA aneuploidy might occur at times after p53 alteration with increasing frequency, as invasive growth begins. Such combination analysis of p53 immunohistochemistry and nuclear DNA ploidy in routine histology may contribute to estimates of malignant potential in preneoplastic and intraepithelial squamous lesions and provide additional information for early detection of BSqCC.

Micropenis and the AR Gene: mutation and CAG repeat-length analysis

Various mutations of the AR gene and expanded CAG repeats at exon 1 of that gene have been reported in patients with hypospadias or genital ambiguity. However, the role of the AR gene has not been systemically studied in those with isolated micropenis lacking hypospadias or genital ambiguity. We studied 64 Japanese boys with isolated micropenis (age, 0-14 yr; median, 7 yr), whose stretched penile lengths were between -2.5 and -2.0 SD (borderline micropenis) in 31 patients (age, 0-13 yr; median, 8 yr) and below -2.5 SD (definite micropenis) in 33 patients (age, 0-14 yr; median, 6 yr). Mutation analysis of the AR gene was performed for exons 1-8 and their flanking introns, except for the CAG and GGC repeat regions at exon 1, by denaturing HPLC and direct sequencing, identifying a substitution of cytosine to thymine at a position -3 in the 3' splice site of intron 1 in a patient with definite micropenis. CAG repeat length at exon 1 was determined by electrophoresis with internal size markers and direct sequencing, revealing no statistically significant difference in the distribution of CAG repeat lengths [median (range) and mean +/- SE: total patients with isolated micropenis, 24 (14-34) and 23.5 +/- 0.38; patients with borderline micropenis, 24 (15-29) and 23.5 +/- 0.53; patients with definite micropenis, 23 (14-34) and 23.5 +/- 0.56; and 100 control males, 23 (16-32) and 23.5 +/- 0.29] or in the frequency of long CAG repeats (percentage of CAG repeats > or =26 and > or =28: total patients with isolated micropenis, 17.2 and 4.7%; patients with borderline micropenis, 19.4 and 6.5%; patients with definite micropenis, 15.2 and 3.0%; and 100 control males, 21.0 and 10.0%). These results suggest that an AR gene mutation is rare and that CAG repeat length is not expanded in children with isolated micropenis.

Female gonadal development in XX patients with distal 9p monosomy

OBJECTIVE

A sex determining gene(s) has been mapped to a approximately 700 kb region distal to the exons of DMRT1 on 9p. The aim of this study was to examine gonadal developmental status in XX patients hemizygous for the 9p sex determining region.

DESIGN

Clinical and molecular studies were performed in an 8-year-old girl with 46,XX,del(9)(p22) (case 1) and in a 2-year-old girl with 46,XX,del(9)(p23) (case 2).

METHODS

Ovarian function status was assessed by gonadotrophin-releasing hormone (GnRH) tests. Hemizygosity for the sex determining region was examined by fluorescence in situ hybridisation and microsatellite analyses for a total of 17 loci on distal 9p.

RESULTS

GnRH tests indicated mild gonadotrophin hyper responses in both cases (case 1: follicle stimulating hormone 9.2-->22.7 IU/l, luteinising hormone 0.7 --> 16.6 IU/l; case 2: follicle stimulating hormone 7.6 --> 38.2 IU/l, luteinising hormone 0.6 --> 9.4 IU/l). Molecular studies showed hemizygosity for the 9p sex determining region in both cases.

CONCLUSIONS

The results, in conjunction with previous reports describing sex development in XX and XY patients hemizygous for the 9p sex determining region, imply that haploinsufficiency of the 9p sex determining gene(s) primarily hinders the formation of the indifferent gonad, leading to a wide range of testicular or ovarian development.

Turner syndrome and Xp deletions: clinical and molecular studies in 47 patients

Although clinical features of Turner syndrome have primarily been explained by the dosage effects of SHOX (short stature homeobox-containing gene) and the putative lymphogenic gene together with chromosomal effects leading to nonspecific features, several matters remain to be determined, including modifying factors for the effects of SHOX haploinsufficiency, chromosomal location of the lymphogenic gene, and genetic factors for miscellaneous features such as multiple pigmented nevi. To clarify such unresolved issues, we examined clinical findings in 47 patients with molecularly defined Xp deletion chromosomes accompanied by the breakpoints on Xp21-22 (group 1; n = 19), those accompanied by the breakpoints on Xp11 (group 2; n = 16), i(Xq) or idic(X)(p11) chromosomes (group 3; n = 8), and interstitial Xp deletion chromosomes (group 4; n = 4). The deletion size of each patient was determined by fluorescence in situ hybridization and microsatellite analyses for 38 Xp loci including SHOX, which was deleted in groups 1-3 and preserved in group 4. The mean GH-untreated adult height was -2.2 SD in group 1 and -2.7 SD in group 2 (GH-untreated adult heights were scanty in group 3). The prevalence of spontaneous breast development in patients aged 12.8 yr or more (mean +/- 2 SD for B2 stage) was 11 of 11 in group 1, 7 of 12 in group 2, and 1 of 7 in group 3. The prevalence of wrist abnormality suggestive of Madelung deformity was 8 of 18 in group 1 and 2 of 23 in groups 2 and 3, and 9 of 18 in patients with spontaneous puberty and 1 of 23 in those without spontaneous puberty. The prevalence of short neck was 1 of 19 in group 1 and 7 of 24 in groups 2 and 3. Soft tissue and visceral anomalies were absent in group 1 preserving the region proximal to Duchenne muscular dystrophy and were often present in groups 2 and 3 missing the region distal to monoamine oxidase A (MAOA). Multiple pigmented nevi were observed in groups 1-3, with the prevalence of 0 of 7 in patients less than 10 yr of age and 15 of 36 in those 10 yr or older regardless of the presence or absence of spontaneous puberty. Turner phenotype was absent in group 4, including a fetus aborted at 21 wk gestation who preserved the region distal to MAOA. The results provide further support for the idea that clinical features in X chromosome aberrations are primarily explained by haploinsufficiency of SHOX and the lymphogenic gene and by the extent of chromosome imbalance in mitotic cells and pairing failure in meiotic cells. Furthermore, it is suggested that 1) expressivity of SHOX haploinsufficiency in the limb and faciocervical regions is primarily influenced by gonadal function status and the presence or absence of the lymphogenic gene, respectively; 2) the lymphogenic gene for soft tissue and visceral stigmata is located between Duchenne muscular dystrophy and MAOA; and 3) multiple pigmented nevi may primarily be ascribed to cooperation between a hitherto unknown genetic factor and an age-dependent factor other than gonadal E.

Screening for mutations of the androgen receptor gene in patients with isolated cryptorchidism

OBJECTIVE

To evaluate the occurrence of mutations of androgen receptor (AR) gene in patients with isolated cryptorchidism.

DESIGN

Controlled clinical study.

SETTING

Yamagata University Hospital, Yamagata and Tokyo Electric Power Company Hospital, Tokyo, Japan.

PATIENT(S)

Patients with isolated cryptorchidism (n = 48) and a control group of men with normal phenotype (n = 20).

INTERVENTION(S)

Blood (lymphocyte DNA).

MAIN OUTCOME MEASURE(S)

Screening of the AR gene in exons 1-8 using single-strand conformational polymorphism analysis.

RESULT(S)

No abnormal band patterns were detected in patients with cryptorchidism or in control subjects within the eight exons of the AR gene.

CONCLUSION(S)

AR gene alterations appear to be an unlikely cause of isolated cryptorchidism.

Impaired urinary water excretion in a three-generation family

We report on a three-generation family (daughter, mother, and maternal grandmother) with a syndrome of inappropriate secretion of antidiuretic hormone (SIADH)-like condition in the absence of inappropriate ADH secretion. In the three females, a water load test showed severely reduced urinary water excretion, with the ratio of urine volume to the loaded water being 10-33% (normal value: 70.2 +/- 7.8%). Urinary AQP2 excretion was normal, as was the DNA sequence of AVPR2 and AQP2. The results suggest the presence of a new dominantly inherited disorder for tubular water resorption.

CAG repeat length analysis and mutation screening of the androgen receptor gene in Japanese men with idiopathic azoospermia

Because androgens are required for normal spermatogenesis, we are investigating abnormalities in the androgen receptor as a possible cause of impaired spermatogenesis in patients with idiopathic male infertility. The CAG repeat length in exon 1 and mutations of the androgen receptor gene were studied in 30 men with idiopathic azoospermia and in 51 fertile men. In men with azoospermia, plasma luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone levels were measured and testicular biopsies were performed. The CAG repeat length ranged from 19 to 30 (mean 23.4 +/- 2.9) and from 17 to 28 (mean 23.7 +/- 3.2) in men with azoospermia and in controls, respectively. There was no significant difference between the 2 groups. In men with azoospermia, the Johnsen testicular biopsy score negatively correlated with plasma FSH (P < .01). However, the Johnsen testicular biopsy score did not correlate with plasma LH and testosterone levels. The CAG repeat length did not correlate with the Johnsen testicular biopsy score, or with plasma concentrations of LH, FSH, and testosterone. No abnormalities in the androgen receptor gene were detected. These facts suggest that the CAG repeat length and alterations in the androgen receptor gene are not associated with the etiology of idiopathic azoospermia.

Breakpoint analysis of Turner patients with partial Xp deletions: implications for the lymphoedema gene location

BACKGROUND

Turner syndrome is characterised by a 45,X karyotype and a variety of skeletal, lymphoedemic, and gonadal anomalies. Genes involved in the Turner phenotype are thought to be X/Y homologous with the X genes escaping X inactivation. Haploinsufficiency of the SHOX gene has been reported to cause the short stature seen in Turner syndrome patients. More recently, mutations of this gene have been shown to be associated with other skeletal abnormalities, suggesting that haploinsufficiency of SHOX causes all the Turner skeletal anomalies. No such gene has yet been identified for the lymphoedemic features.

METHODS

Fluorescence in situ hybridisation (FISH) analysis with PAC clones on nine patients with partially deleted X chromosomes was performed.

RESULTS/DISCUSSION

The Turner syndrome stigmata for each patient are described and correlation between the breakpoint and the phenotype discussed. A lymphoedema critical region in Xp11.4 is proposed and its gene content discussed with respect to that in the previously reported Yp11.2 lymphoedema critical region.

L-DOPA produced nitric oxide in the vitreous and caused greater vasodilation in the choroid and the ciliary body of melanotic rats than in those of amelanotic rats

The nitrogen cycle initiates direct reduction of N2 to NH3 by enzymatic reactions. We hypothesize that L-dihydroxyphenylalanine (L-DOPA), a catecholamine, could be a source of nitric oxide (NO). In order to determine whether L-DOPA generates NO and induces any biological change in the eye, we measured the generation of NO in vitro and in vivo, and investigated the histopathological changes caused by injection of L-DOPA into the vitreous of rats. We also hypothesized that melanin granules may affect the generation of NO during the metabolism of L-DOPA, since L-DOPA is a precursor of melanin in the brain and the eye. Therefore, we compared the effects of L-DOPA on the generation of NO between amelanotic and melanotic rats. NO was measured as diffusion currents by NO electrodes. In vitro, various concentrations of L-DOPA (5, 29.9, 79.4, 152.7, and 249 microM) were added to the medium. The inhibition of NO generation by 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazole-1-oxyl 3-oxide (carboxy-PTIO) was tested. In vivo, NO generation in the vitreous of rats was measured and the eyes were enucleated under anesthesia after L-DOPA injection. The ocular tissues were subjected to histological examination. NO was produced from L-DOPA in a dose-dependent manner and was scavenged by carboxy-PTIO in vitro. NO in the vitreous of melanotic rats was generated from L-DOPA. Histological examination with hematoxylin-eosin staining revealed vasodilation in the ciliary vessels and the choroid after L-DOPA injection. Both effects were greater in melanotic rats than in amelanotic rats. The vasodilation may be attributable to NO as well as to superoxides, which can be regulated by the existence of melanin.

Mutation screening and CAG repeat length analysis of the androgen receptor gene in Klinefelter's syndrome patients with and without spermatogenesis

BACKGROUND

Mutations of the androgen receptor (AR) gene give rise to a wide array of phenotypic abnormalities. A systematic analysis of the AR gene in patients with 47,XXY has not previously been performed.

METHODS

Mutations of the AR gene and expansion of the CAG repeats in exon 1 of the AR gene were studied in 13 patients with Klinefelter's syndrome either with (n = 1) or without (n = 12) spermatogenesis.

RESULTS

No abnormalities in the AR gene were detected by single strand conformational polymorphism analysis. The CAG lengths ranged from 17 to 27 (mean +/- SD 22.8 +/- 3.3, median 23) for Klinefelter patients or from 17 to 28 (mean +/- SD 23.2 +/- 2.6, median 23) for control subjects. X-inactivation analysis for the methylation status of the AR gene was performed in seven patients who were heterozygous for CAG repeats of different length, showing that the longer CAG repeat alleles underwent random but more frequent inactivation in five patients and skewed inactivation in two.

CONCLUSIONS

An AR gene abnormality does not constitute an important factor for impaired spermatogenesis in patients with Klinefelter's syndrome.

Compound effects of point mutations causing campomelic dysplasia/autosomal sex reversal upon SOX9 structure, nuclear transport, DNA binding, and transcriptional activation

Human mutations in the transcription factor SOX9 cause campomelic dysplasia/autosomal sex reversal. Here we identify and characterize two novel heterozygous mutations, F154L and A158T, that substitute conserved "hydrophobic core" amino acids of the high mobility group domain at positions thought to stabilize SOX9 conformation. Circular dichroism studies indicated that both mutations disrupt alpha-helicity within their high mobility group domain, whereas tertiary structure is essentially maintained as judged by fluorescence spectroscopy. In cultured cells, strictly nuclear localization was observed for wild type SOX9 and the F154L mutant; however, the A158T mutant showed a 2-fold reduction in nuclear import efficiency. Importin-beta was demonstrated to be the nuclear transport receptor recognized by SOX9, with both mutant proteins binding importin-beta with wild type affinity. Whereas DNA bending was unaffected, DNA binding was drastically reduced in both mutants (to 5% of wild type activity in F154L, 17% in A158T). Despite this large effect, transcriptional activation in cultured cells was only reduced to 26% in F154L and 62% in A158T of wild type activity, suggesting that a small loss of SOX9 transactivation activity could be sufficient to disrupt proper regulation of target genes during bone and testis formation. Thus, clinically relevant mutations of SOX9 affect protein structure leading to compound effects of reduced nuclear import and reduced DNA binding, the net effect being loss of transcriptional activation.

Characteristics of wine produced by mushroom fermentation

Saccharomyces cerevisiae is the main microorganism used in wine brewing, because this microbe has potent ability to produce alcohol dehydrogenase. We have recently discovered that some genera of mushroom produced alcohol dehydrogenase, and made wine by using a mushroom in place of S. cerevisiae. The highest alcohol concentration in this wine was achieved with Pleurotus ostreatus (2.6 M, 12.2%). In the case of Agaricus blazei, the same alcohol concentration (1.7 M, 8%) was produced under both aerobic and anaerobic conditions. This wine produced by A. blazei contained about 0.68% beta-D-glucan, which is known to have a preventive effects against cancer. The wine made by using Flammulina velutipes showed thrombosis-preventing activity, giving a prolonged thrombin clotting time 2.2-fold that of the control. Thus, the wine made by using mushroom seems to be a functional food which can be expected to have preventive effects against cancer and thrombosis.

Ultra-high-resolution scanning electron microscopic studies on the membrane system of the rat parietal cells after tetragastrin stimulation

The membrane system of the rat parietal cells in the resting state and after stimulation with tetragastrin (gastrin) was examined by ultra-high-resolution scanning electron microscopy after removal of the cytoplasmic matrix by the aldehyde-osmium-DMSO-osmium procedure. The intracellular canaliculus was lined with numerous microvilli. Viewed from the cytoplasmic side, the intracellular canaliculi appeared as an arborized system of cactus-like structures with numerous holes about 100 nm in diameter corresponding to the basal openings of the microvilli. The intracellular canaliculi were more developed after gastrin stimulation than in the resting state. In resting cells, most of the tubulovesicles were isolated, 100-200 nm in diameter, spherical or tubular in shape. After gastrin stimulation, these structures were interconnected by slender tubules of about 30 nm in diameter forming together tubulovesicular network. Stereo SEM views clearly demonstrated that the tubulovesicular network was connected with the intracellular canaliculus by the slender connecting tubulus. The increase in the canalicular membrane area and the depletion of tubulovesicles is explained by the transfer of the tubulovesicular membrane to the intracellular canaliculus. In the resting parietal cell, the microvilli are slender and their interior is packed with microfilaments. After gastrin stimulation, the microvilli are swollen and their interior is edematous. These morphological changes seem to indicate the accumulation of fluid in the microvilli after gastrin stimulation.

Undermasculinized genitalia in a boy with an abnormally expanded CAG repeat length in the androgen receptor gene

We report an 11-year-old boy with undermasculinized genitalia and an abnormally expanded CAG repeat length at exon 1 of the androgen receptor (AR) gene. He had microphallus and scrotal hypospadias with chordee, and underwent urethroplasty at 4 years of age. At 11 years of age, a gonadotropin releasing hormone (GnRH) test yielded a relatively high leutinizing hormone (LH) response (0.7-->20.4 IU/l) and a relatively low follicle-stimulating hormone (FSH) response (1.7-->4.8 IU/l), and an human chorionic gonadotropin (hCG) test showed sufficient responses of testosterone (0.7-->23.0 nmol/l) and dihydrotestosterone (0.38-->2.95 nmol/l). The CAG repeat length was 44 for the boy and ranged from 12 to 32 for 100 control males. The DNA sequences of the AR gene were normal for the exons 1-8 and for the splice donor, splice acceptor and branch sites. The markedly expanded CAG repeat length appears to be relevant to the undermasculinized genitalia of this boy, because such an expandsion, which has previously been reported only in spinal and bulbar muscular atrophy, is known to reduce AR function.